Second day of the first CAST suitcase flight commenced with a weather comment from Mission Scientist 2, “How glorious, sunny and warm it was in Chuuk this morning”, much to the disgruntlement of those in Guam staring out at the driving rain.
The BAe-146 took off at 11.00 late morning and was en route to the Equator to sample boundary layer air. A high extent of variability in halogenated species was spotted, raising our hopes and the bar high for the suitcase flights planned for next week. A couple of profiles for B827 flight were completed up to 12 kft with extensive low level profiling. This would give us the best optimised vertical cross-sections through the lower troposphere and allow for altitude-dependent measurement analysis. This includes the impact of both easterly and westerly winds, the well-mixed low troposphere, and in-mixing of continental outflow and clean oceanic air. All VSLS, including bromoform, chloroform, dichloromethane, bromochloromethane and others were measured, with highest concentrations at lower altitudes. Highlights of today’s late morning flight included nearing the Equator at 1°N, 151°E, sampling the boundary layer at various heights. Scientists on the plane were graced with seeing stunning views of the atolls around Chuuk as they profiled the air above them.
After refuelling, BAe-146 was ready for the last flight returning to Guam. Mission Scientist 2 reported stunning views outside BAe-146 windows, and random ozone fluctuations were noted and VSLS concentrations were recorded with variability noted with atitude. After two loops of the atolls, the flight’s destination was Guam. A couple of low level profiling up to 12 kft were performed, and the aeroplane landed safe and sound at 19.30 (local time). The flight was followed by a hard down day, including a true British style barbecue and football match in the rain to let the crew rest and relax. Excited about the next CAST flight already!